// Copyright 2014 The Chromium Authors. All rights reserved.
// Use of this source code is governed by a BSD-style license that can be
// found in the LICENSE file.

#ifndef NET_SPDY_SPDY_PINNABLE_BUFFER_PIECE_H_
#define NET_SPDY_SPDY_PINNABLE_BUFFER_PIECE_H_

#include <stddef.h>

#include <memory>

#include "base/strings/string_piece.h"
#include "net/base/net_export.h"

namespace net {

class SpdyPrefixedBufferReader;

// Helper class of SpdyPrefixedBufferReader.
// Represents a piece of consumed buffer which may (or may not) own its
// underlying storage. Users may "pin" the buffer at a later time to ensure
// a SpdyPinnableBufferPiece owns and retains storage of the buffer.
struct NET_EXPORT_PRIVATE SpdyPinnableBufferPiece {
public:
    SpdyPinnableBufferPiece();
    ~SpdyPinnableBufferPiece();

    const char* buffer() const
    {
        return buffer_;
    }

    size_t length() const
    {
        return length_;
    }

    operator base::StringPiece() const
    {
        return base::StringPiece(buffer_, length_);
    }

    // Allocates and copies the buffer to internal storage.
    void Pin();

    bool IsPinned() const { return storage_ != nullptr; }

    // Swaps buffers, including internal storage, with |other|.
    void Swap(SpdyPinnableBufferPiece* other);

private:
    friend class SpdyPrefixedBufferReader;

    const char* buffer_;
    size_t length_;
    // Null iff |buffer_| isn't pinned.
    std::unique_ptr<char[]> storage_;
};

} // namespace net

#endif // NET_SPDY_SPDY_PINNABLE_BUFFER_PIECE_H_
